Our family is just my dd and me, and we don't let that stop us!!!
Our last trip was when dd was 5 1/2, and a friend and her daughter came down for a few days, then my mom came down for a few days. My biggest complaint... not enough "us" time! Fun with others, but when it was just us two, we had a BLAST. Our highlights were not necessarily the attractions, but just being away from home, pressures and being silly together.
Hmmm things to make disney extra special... well nothing. As always at disney, it just happens. From the night (technically morning) that we checked in and the cm gave my dd a couple of beanies, to the mgm bus driver that asked "how do I get to mgm?", to our first ever ToT ride, it was the LITTLE things that made it special. I wouldn't sweat the big stuff. We did the princess breakfast in Norway, which was great, but not as special as playing shadow tag in the parking lot before hand. Or chatting with a family from nj on the bus. Or riding HM 5 times in a row. Or getting a "bear hug" from baloo.
Trust me, if you put yourself in "play" mode, everything will be special to a five year old. Me, I haven't relaxed and had fun like that in ages.